Probes are mechanical tools for measuring electrical characteristics of microscopic electronic devices (e.g., semiconductor devices). As well known, a semiconductor device has a plurality of pads for communicate signals with an external electronic system. The semiconductor device executes internal operations with electrical signals input through the pads, and then transfers processed results to the external electronic system through the pads. During this, the probes are arranged on a printed circuit board of a probe card, physically contacting with the pads, so they form electrical paths for signal transmission with the external electronic system or device.
Probe cards, as well known, can be classified into needle, vertical, and cantilever types in accordance with kinds of probes. The needle type probe card has a disadvantage of distortion with horizontality and alignment due to repetitive use because its probe needles are insufficient in restoration. Additionally, since the probe needles of the needle type probe card are large in size with themselves, it is improper to be employed in testing a highly integrated semiconductor device. The vertical type probe card is otherwise appropriated as being suitable for testing a highly integrated semiconductor device because it is smaller in size and its probes are arranged in narrower intervals. But, in the vertical probe card, as force contacting a probe to a pad is oriented toward a lengthwise direction of the probe, it also has a problem of deformation due to insufficient restoration force.
Different from those types of probes, in a typical cantilever probe card, tips for contact with pads are bonded to ends of cantilever type beam portions. The beam portions are adhered to a printed circuit board in parallel with the tops of the pads. According to this, the force for contacting probes (i.e., the tip portions) of the cantilever type probe card to the pads operates vertically to the lengthwise direction of the beam portions. Such a structure of the cantilever type probe card provides the maximum restoration force thereto.